This project is designed to study microangiopathy restrospectively from sequential sections of temporal bones of diabetic patients using light microscopic and appropriate histochemical technics. Effects of age of onset, duration of diabetes and endocrine status will be correlated with the morphology. Prospective studies will be undertaken utilizing a) surgical specimens of mucosa and the subjacent lamina propria and/or b) temporal bones obtained at autopsy to study the basement membrane thickness of the capillaries of both the middle and inner ear (especially of the stria vascularis).